Detergent briquette



Patented Aug. 14, 1945 UNITED STATES PATENT OFFICE nn'maoz r i armuam I p v "r$tnim2.m tiltfai:

New York, N. Y., a corporation of Virginia ation January 31, 1942,

No Drawing.

4 Claims. (Ci. 252-135) for washing dishes, milk cans and the like, particularly where the operation is continuous or prolonged, have presented the serious problem of maintaining an alkali concentration in the wash tanks between desirable and restricted limits. Commercial experience has shown that this may be accomplished in a dependable and virtually automatic manner by dissolving alkaline briquettes in suitable auxiliary equipment and dispensing the resulting solution into the wash tanks at a predetermined rate. A very considerable amount of research has been carried out in view of developing detergents having chemical and physical characteristics satisfactory for this purpose.

T e problem presented involves not merely the production of a material or mixtures of materials having the desired detergent characteris-. tics but also the development of a product which, in addition to meeting that requirement, can be economically produced in the desiredv physical form possessing other essential physical characteristics.

For instance, it is desirable that the detergent be in briquette form; that the briquettes be sufficiently hard and strong to withstand ordinary handling; be chemically and physically stable and non-deliquescent so as to withstand storage and the necessary handling and of such structure as will not disintegrate under the conditions of use.

Inasmuch as the control of the rate at which the alkali is dispensed into the washing operation largely depends upon the dissolving rate of the briquette, it is desirable that the briquette not only have a satisfactory degree of uniformity in its composition but also that it have a uniform solubility rate.

It is, of course, also essential that the composition of the cleansing solution be such as to avoid harmfully affecting the material being washed either by attacking the material or by forming deposits or coatings thereon. It is further essential that the composition of the detergent be such as to avoid deleteriously affecting the parts of the mechanical washer and the deposition of scale in the various chambers thereof.

It has been proposed to produce detergent briquettes for such use by fusing the detergent or detergent mixture and casting thefused material by drawing it of! into molds to cool. For example, briquettes have been produced by fusing mixtures of trisodium phosphate and soda ash. However, the relatively high temperatures required to fuse the detergent or detergent mixtures have been a decided handicap in the production of satisfactory detergent briquettes, as many substances,the presence of which is highly desirable in detergent mixtures, are driven off or decomposed at temperatures below their fusion point or at temperatures necessary for fusing other desirable constituents.

This temperature requirement has not permitted the incorporation in detergent mixtures so produced of many very effective water conditioners and surface active agents such as synthetiddetergent and wetting agents. Consequently, the use of such fused detergent briquettes has not been wholly satisfactory. For instance, particularly under adverse water conditions, their use has resulted in the precipitation of natural hardness of the water supply and the tendency to form scale on the inner surfaces of the mechanical washers with which the de- 80 tergent is used. Rapidity of this scale formation depends upon the degree and nature of the hardness of the water and, in general, increases with the concentration of hardness of the water supply. If not periodically removed, this scale interferes with the normal functioning of the equipment. Further, this precipitated hardness interferes to a greater or less extent with the cleansing operation.

The presence of a water conditioner such as tetrasodium pyrophosphate (Na4PaO-z), sodium tetraphosphate (N86P4013) or sodium hexametaphosphate (NasPaOra) in the alkaline solution tanks of the mechanical washers has been found to inhibit or greatly retard scale formation. Also the addition of surface active agentshas been found further to enhance the cleansing action and to afford improved rinsing. However, for the reasons stated above, the incorporation of these materials in fused anhydrous detergent briquettes has been impractical.

Detergents have heretofore been produced in block form by crystallization or solidification of the detergent or detergent mixtures from aqueous solutions; for instance, by the evaporation of water therefrom or by causing a chemical or surface active agents.

.. tetraphosphate as thereof with the detergent. lhe resulting blocks of detergent material have usually been reduced to a granular or powdered form before use.

Ithasalsobeenproposed tousethesedetergent blocks as such in detergent operations. However, so far as I am aware, the detergent blocks so produced prior to my invention have fallen short oi the requirements essential to their satisfactory commercial use in mechanical washing opera- The detergent briquette oi! my present invention may be formed without resort to high temperatures and its constituents and proportions thereof may be varied over a considerable range to meet the requirements of the particular washing operations in which they are to be used. Further, the physical limitations and deficiencies common to previous detergent briquettes are overcome. Myimproved briquettes consist or a dense crystalline te of relatively uniform composition. They are hard and strong and physically stable, being capable of withstanding the conditions of shipment and storage essential to ultimate commercial use without material deterioration, disintegration or deiiquescence.

, They do not disintegrate under normal conditions of use and have a uniform solubility rate. Further, there are no objectionable chemical changes in the composition 01' my. briquettes. Also, since they can beproduced without resort to high temperatures, various desirable addition agents unstable at higher temperatures may be incorporated therein to meet special water conditions or detergent requirements. Accordingly; objectionable precipitations of natural hardness of'the water used may be inhibited or greatly reduced and the detergent action of theresulting washing solution materially improved. Further, the congealing and hardening time of my briquettes during molding is sufllciently rapid to permit their economical commercial production.

The detergent mixture of which my improved briquettes are composed is prepared by com poimding, at'a moderate temperature, controlled proportions of trisodium phosphate, sodium silig 8,383,105 physicalimion o! the water or a proportion I can produce briquettes of excellent physical characteristics containing as high as about 35% anhydroustrisodium phosphate.

In the compoimdin'g of my briquettes, the trisodirnn phosphate may be introduced, in the form of the ordinary commercial hydrated product gena'ally represented by the formula NasPO4.12H:'O or a product having a lower water content. the dodecahydrate contains 56.8% water. However, repeated analyses indicate that the water content of the trisodium phosphate dodecahydrate which I have used in the development of my improved briquette is approximately 53%.

tly, the proportions of the dodecahydrate specified herein are based upon the latter figure. If an excesive water content inthe mixture is to be avoided, a trisodium phosphate having a water content lower than the dodecahydrate should be used where'the anhydrous trisodium phosphate content of the product'is to exceed approximately 30% by weight.

Materials that react under the process conditions to form trisodium phosphate, for instance phosphate and caustic soda, may be substituted for an equivalent proportion of trisodium phosphate, appropriate allowances being made tor the water content of such reacting materials and water produced by the reactions.

, The sodium silicate constituent of my briquettes should have an Na:O:SiO= ratio of not less than 1 nor greater than 2. I have obtained excellent mults by supplying the sodium silicate in the form oi. water glass of 41 B. gravity and consisting of 8.9% "No.20, 23.7% $102 and 62.4% water, and reactin the water glass with caustic soda insufllcient proportion to produce a sodimn silicate oi. the desired Naz0:SiOz ratio. Other water glass or sodium silicate in solid 'form may invention by making appropriate allowance for difierences in composition. For example, instead of the use of water glass and suiiicient caustic soda to react therewith to form the metasilicate, sodium metacate, sodium carbonate, water and either sodium hexametaphosphateor sodium tetraphosphate or a mixture of the two, as essentialv ingredients. Advantageously, it may also contain one or more The inclusion of the metaphosphate or the ingredients or the briquettes is desirable with respect to the detergent operation where the available wash water is hard. However, I"have round the addition of either 01 these phosphates in controlled proportions to the detergent mixture to have a decided influence upon the range of proportions of other ingredients which will result in briquettes having satisfactory physical structure. In this respect, the use of sodium tetraphosphate or sodium hexa'meta ph p of the pyrophosphate as a water conditioning constituent. For example, I have determined by extensive research that where tetrasodium pyrophosphate is incorporated in briquettes oi the type herein described, not more than about 15% by weight of anhydrous trisodium phosphate can be incorporated in the briquettes without detri- 'men tally afiecting their physical structure. I

have further discovered that by using approximately the same proportifins of either the sodium tetraphosphate or the sodium hexametaphosphatc has a decided advantage over the use silicate as such may be substituted wholly or in part for the water glass and caustic soda equivalent. when such substitution is made, due allowance should also be made for the amount of water which would otherwise be formed by the reaction between the water glass and caustic soda.

'lhc caustic soda maybe supplied in solid form such as the usual commercial grade or. about 76% R820. However, other forms of caustic soda,

such as the commercially available 50% solution,

may be substituted ,provided appropriate allowance is made for th dil lerence'in composition,

The carbonate may conveniently be supplied as anhydrous soda ash in proportions ranging from-about 10% to about 50% by weight, and the proportions stated in the several formulae up.- hearing herein are based upon the use thereof. However, it may be supplied in the form of hydrates such as mono or deca hydrate appropriate :lllowanee being made for diilerences in composi- Similarly, =the sodium hexametaphosphate or sodium iah'aphosphate may be supplied in the usual anhydrous form and proportions th'ereor appearing herein have reference to such material:

, Before defining the range 01' proportions'oi the various ingredients incorporated in my improved briquettes, I shall describe a novel process which may be used with advantage in compounding and to preparing the same.

The compounding of my improved detergent is advantageously carried out in a conventional steam-jacketed kettle equipped with a stirring device. I have obtained excellent results in preparing and in duplicating the composition and structure of the briquettes by adhering to the following procedure: The predetermined amounts of water glass, trisodium phosphate, caustic soda and additional water, if any is required, are placed in the kettle and heated with'constant agitation until the mass is fluid. The temperature is then maintained at a maximum Just beyond which substantial evolution of steam would occur with a resultant material loss in water content. Higher temperatures are to be avoided as it is desirable to reduce to a minimum the amount of water lost during the heating operation and to avoid objectionable decomposition of less stable ingredients. By minimizing the water loss the proportion-of water in the product may be effectively controlled by regulation of the total amount of water added to the batch.

The maximum temperature to which the material is heated, and at which it is held, depends primarily-upon the concentration of the solution in the fluid mass and is usually found to be within the range of about 90-110 C. The fluid mass is held at this temperature until the mass clarifles, advantageously until maximum clarity is obtained. This usually requires from to 20 minutes, depending upon the composition and amount of solute.

After clarification of the mass the predetermined amount of soda ash is then added and thoroughly mixed with the fluid mass. If the it prior to the addition of the soda ash. various surface active agents capable of withstanding the necessary pouring temperatures in an alkaline enaddition of soda ash results in a decrease in temperature to a point at which the mass is too viscous for flnal pouring, the temperature may be increased until adequate fluidity is obtained, care being taken to avoid temperatures which would result in the material loss of water. The sodium hexametaphosphate or odium tetraphosphate is advantageously added and the mass in the kettle just prior to withdrawal from the kettle. Care should be exercised in the incorporation of these materials with the hot mixture in the kettle to avoid a possible violent reaction. The temperature should be at a minimum for adequate pouring fluidity, should not exceed 95 C., and preferably should be below 90 C.

The mixture is then drawn of! into suitable molds and allowed to congeal until the briquettes have developed sufllcient mechanical strength to permit their removal from the mold. The necessary molding time will generally vary from about one hour to several hours, depending upon the composition of the mixture. Where a sodium silicate other than water glass is used. it should be placed in the kettle at that stage of the operation where the water glass would have been introduced.

On cooling, detergent compositions of this type seem to expand somewhat and this, combined with their tendency to adhere to metalsurfaces of the molds has previously presented consider difiiculty in the molding of detergent materials. I have found that, by usingflexible briquette molds, such a molds made of rubber or similar materials, these difllculties are eliminated.

Where it is desirable to incorporate in the briquettes a so-called surface active agent, such material may be introduced into the mixture just prior to withdrawal from the kettle. However, where such addition agent is in solid form and has a relatively slow rate of solubility, I prefer to add thoroughly mixed into a vironmentmay be so incorporated in my brifquettes to meet special conditions encountered in specific detergent operations for which the briquettes are intended; for example, a product consisting principally of sodium lauryl sulfate, marketed under the tradename "Orvus", orone consistlng principally of sodium dodecyl benzene sulfonate, marketed under the tradename Nacconol each of which I have used to advantage.

The addition of even a fraction of 1% or many of the so-called surface active agents or synthetic detergent or wetting agents has been found materially to reduce the dissolving rate of the resulting briquette. This effect has been found to increase generally as the amount of the agent is increased. Also, under similar conditions of preparation, the addition of-many of these surface active agents somewhat increases the molding time. Though, for some purposes, a reduced dissolving rate is undesirable, the addition of a predetermined amount of a surface active agent is of value in controlling the dissolving rate to meet a specific requirement in this respect. The primary purpose of the addition of these surface active agents is to increase the wetting power of the washing solution and so tend to improve the detergent and rinsing properties thereof. The addition of many of these materials in proportions as small as 0. has a noticeable effect.

One of the advantages of my invention is that.

such surface active agents may be incorporated in my briquettes, if desirable, either for controlling the dissolving rate or for increasing the wetting power of the washing solution. However; under many conditions encountered, the detergent mixture need not be so supplemented.

While the proportion of the various ingredients used may be varied over a considerable range without destroying the desirable physical or mechanieal properties of the resulting briquette, I have found the permissible range of variation to be rather sharply defined. An increase in the proportion of trisodium phosphate with a corresponding decrease in soda ash, other conditions being the same, tends to decrease the congealing or molding time of the resultant briquette. How ever, the proportion of anhydrous trisodium-phosphate which may be added without detrimentally affecting the physical characteristics of the briquette is greatly increased by the addition of the meta or tetra phosphate.

Generally, it may be stated that the permissible proportion of anhydrous trisodium phosphate is increased as the proportion of sodium hexametaphosphate or sodium tetraphosphate is increased. By the addition of about, 15% of either the metaphosphate or the tetraphosphate the proportion of trisodium phosphate which may be added with advantage is increased to about 35% by weight. The addition of anhydrous trisodium phosphate in greater proportions results in briquettes which have a tendency to develop weak and uneven structures. Proportions of the metaphosphate or the tetraphosphate as low as about 1% by weight have a noticeable effect in this respect.

Generally, when the proportion of trisodium phosphate approaches the upper limit of the range, 1. e. about 35% by weight, the silicate content should approach its lower limit and its alkalinity approach that of the metasilicate' in order to obtain most satisfactory conditions with respect to molding time and structure of the resultant briquette.

Where the proportion of anhydrous trisodium phosphate added is less than about 1% by weight, I have found the briquettes to be so slow in congealing that the molding time is excessive. Further, the proportion of sodium silicate which can be employed without detrimentally affecting the physical structure of the briquette is limited where less than about 1% by weight of anhydrous trisodium phosphate is added. The addition of the sodium metaphosphate or the sodium tetraphosphate in proportions approximating by weight has a tendency to relieve these conditions somewhat.

. I have found the desirable proportions of anhydrous sodium silicate added to the mixture to be within the range of about 1 to about 22% by weight. As the proportion of anhydrous sodium silicate exceeds this maximum, the molding time becomes excessive and, when the proportion of anhydrous sodium silicate added is increased to about 25%, briquetting difliculties are experi enced. Where less than about 1% anhydrous sodium silicate is added, the physical characteristics of the briquettes are impaired. Where water glass such as previously described or other sodium silicate having a ratio of NazOzsioz less than 1 is used, I add caustic soda in proportions suillcient to combine with the water glass to form the metasilicate in which the ratio of NazOZSiOz is unity but not in excess of that required to 'lorm the orthosilicate in which the ratio of NasO:SiOz is 2. In general, best results are obtained Where the proportion of caustic soda so employed is within the range required to produce a mixture of metasilicate and orthosilicate in proportions of from 1 to 2 to 2 to 1. However, satisfactory results may be obtained with a proportion of anhydrous sodium silicate constituent within the range of about 1% to about 22%, whether it be the metasilicate, the orthosilicate or a combination of the two, including a silicate I having. an NazOtSlOz molar ratio of 1 :l,

which may be designated sesquisilicate. This maximum may be increased to about 25% but, particularly where the silicate constituent is the orthosilicate, less desirable physical structure and molding characteristics are ordinarily obtained when such larger proportions of silicate are used.

Besides advantages with respect to water-conditioning and extending the permissible range of trisodium phosphate, the addition of sodium tetraphosphate or sodium metaphosphate has a tendency to decrease the molding time and improve the structural characteristics of the resultant briquette where the proportion of sodium silicate constituent added is in the upper range. When the sodium silicate constituent is at the extreme upper portion of the range, and particularly when its alkalinity closely approximates that of orthosilicate, larger proportions of the sodium tetraphosphate or the sodium metaphosphate, even in excess of 15%, may be added with advantage, for example about 20% of the sodiumtetraphosphate may advantageously be used.

The amount of water present in the detergent composition is of major importance both with respect to molding time and mechanical structure of the resultant briquette and also its detergent capacity. It is essential that sumcient water be present during the processing to produce under processing conditions a mass sufllciently fluid to permit satisfactory mixing and pouring intothe molds and have satisfactory molding character- I water to permit istics. However, the addition of an excess of water is to be avoided since the processing preferably does not involve conditions under which excess water would be eliminated.

I have found the permissible range of proportions of water in my briquetted product to be from about 30% to about 40% by weight. It is necessary that the product contain sufllcient satisfactory pouring and molding but an increased amount of water in the product results in a corresponding reduction in the alkali content of the briquette. The proportion of water present also has a distinct effect upon the physical characteristics of the briquette. Proportions of water in the product up to about 40% by weight do not materially increase the congealing time or detrimentally affect the physical structure of the briquette. However, proportions of water in excess of about 40% have been found toincrease the molding time to impracticability and to affect adversely uniformity of structure of the resulting briquette. When the water content much exceeds this upper limit, there is a tendency toward segregation; during the congealing period.

The optimum amount of water present in the finished product appears to depend to a considerable extent upon theproportions of other ingredients present. Usually, more satisfactory results are obtained where the proportion of water is not much in excess of that required to give satisfactory fluidity for pouring.

In determining the quantity of water, if any, to be added as such in the compounding operation, due consideration must be given to the amount of water present in the various constituents either as water of crystallization or otherwise and of water formed by chemical reactions. A small amount of water may be vaporized or lost during the compounding of the detergent mixture, particularly if the higher temperatures be used. The amount of water thus lost is usually of no particular consequence,- However, if the amount of water thus lost is excessive, additional water may be added to the batch.

Where'large proportions of ingredients of high water content are used, the resultant mixture may contain a greater proportion of water than is permissible in the briquetted product. Under such circumstances, the excess water may be driven oil as vapor during'the'compounding.

Where the anhydrous trisodium phosphate constituent is at the extreme upper end .of the range for that ingredient and the tetraphosphate or metaphosphate is added in proportions in excess of 15% for improving the molding characteristics, it may be necessary to decrease the soda ash content to an amount even below 10%.

Where the proportion of anhydrous sodium silicate is at about the middle of the prescribed range for that constituent, and particularly when the alkalinity of the silicate constituent ap--,

proaches that of sodium sesquisilic'ate, the proportion of sodium hexametaphosphate or sodium tetraphosphate used may be varied throughout the stated range without materially benefitting the physical structure of the resultant briquette.

Where the presence of a surface active agent, such as the previously mentioned synthetic detergent and wetting agents, is desirable, a maximum of about 5% has been found suflicient for most purposes where a detergent in briquetted form can advantageously be adopted. Usually, smaller proportions are sufficient. When a proportion as high as 5% is employed, most satisfactory physical structure is usually obtained when the equivj asaams 'alent' oi sodium silicate added does not much exceed about 15% of the product by weight and the alkalinity oi the silicate approaches that of the-sesqmsilicate.

The following formulae arepresented as specine examples of proportions of the several ingredients which'have been used with advantage in the preparation of my improved briquette. It 'will be understood that my invention is not limited to products prepared from the particular It is possible that the tetraphosphate or the metaobserveda slight temperature increase when the sodium tetraphosphate or the sodium hexa metaphosphate is added, which suggests thepossibility oi chemical reaction. I am at present unable definitely to state the nature or extent of such chemical reaction-, it in ia'ctit'does occur.

' phosphate reacts with one or more of the other formula shown. In each instance' the proportions are by weight.

Batch No.

brew:

ed water The trisodium phosphate ingredient used in Examples 1 and 2 was the dodecahydrate. However, in Examples 3.! and 5; in order to avoid introducing into the batch a proportion of water in excess of that desired in the product, the monohydrate was substituted for a portion of the dodecahydrate. In Example 3, the trisodium phosphate added consisted of 59% dodecahydrate and 2.6% monohydrate and, in Examples 4 and 5, this constituent consisted of 55.7% dodecahydrate and 10% monohydrate. In Examples l to 4, inclusive, the alkalinity of the sodium silicate constituent was equivalent to that of the metasilicate and, in Example 5, it was equivalent to that of the orthosilicate.

In the following tabulation, the proportions of trisodium phosphate and water glass constituents have been reduced to an anhydrous basis with the water added as trisodium phosphate hydrate and as water glass included in the approximate percentage of total water.

Batch No.

Trisodium phosphate 19. 9 24. 9 a 35. i as. l Soda ash 39. 2 33. 2 22. 1 12.9 12. 9 Sodium siilcate 2. 9 2. 0 2. 9 2. 9 2. 9 Tetraphosphate- 3 10 16 Metaphosphate. Total water (approx.) 36 34 36 34 34 Examples 1 to 4, inclusive, illustrate particularly the way in which the anhydrous trisodium phosphate constituent may be increased by the *with certainty the nature ingredients but I am at present unable, by chemical analysis of the final product, to determine or extent of 'such reaction.

addition of successively larger proportions pt sodium tetraphosphate. Example 5 similarly illustrates the manner in which the proportion of trisodium phosphate may be increased by the addition of sodium hexametaphosphate.

In the foregoing specific examples, the various ingredients were compounded by the process previously described wherein the proportion of water remaining in the product was controlled bythe proportion of total water entering into the batch and avoiding temperatures at which there would be any material loss of waterby vaporization.

In the compounding of these ingredients I have Exoepting .that the variousingredients must be compounded at a temperature at which the mass is sufllciently fluid tor pouring a'n'd'molding, my

invention is, not dependent upon the particular process used. Preferably, the compounding temperature. should not much exceed that-at which fluidity necessary for molding is obtained.

This application is in part a continuation of my 'co-pending application Serial No. 389,819, filed April 21, 1941.

I claim! 1. A detergent briquette physically stable, hard, strong and non-deliquescent consisting of a dense crystalline aggregate consisting essentially of the following ingredients in proportions by weight within the respective indicated ranges: trisodium phosphate about 1% to 35%, sodium silicate about 1% to 25%, soda ash about 10% to 50%, total water about 30% to 40%, a phosphate of the class consisting of sodium hexametaphosphate and sodium vtetraphosphate about 1% to 15% and an alkali-stable surface active agent up to about 5%, the NazOzSiOz ratio of the silicate being not less than 1: 1 nor greater than 2:1.

2. A detergent'briquette physically stable, hard,

strong and non-deliquescent consisting of a dense crystalline aggregate consisting essentially of the following ingredients in proportions by weight within the respective indicated ranges: trisodium phosphate about 1-% to 35%, sodium silicate about 1% to 25%, soda ash about 10% to 50%, total water about 30% to 40% and sodium tetraphosphate about 1% to 151%, the Naaozsioa ratio of the silicate being not less than 1:1 nor greater 1% 'to 25%, soda ash about 10% to 50%, total water about 30% to 40% and sodium hexametaphosphate about 1% to 15%, the NazO:SiOz ratio of the silicate being not less than 1:1 nor greater than 2:1.

4. A detergent briquette physically stable, hard,

strong and non-deliquescent consisting of a dense crystalline aggregate consisting essentially oi the following ingredients in proportions by weight within the respective indicated ranges: trisodium phosphate about 1% to 35% sodium silicate about 1% to 25%, soda ash about 10% to 50%, total water about 30% to 40% and a phosphate of the class consisting of sodium hexametaphosphate and sodium tetraphosphate about 1% to 20%, the NaaOzsiOz ratio of the silicate being not-1e than 1 1 nor greater than 2:1. JAMES DOUGLAS MacMAHON.

v cx'nmxcanorcomcnox. 1 fetent No. 2,382,165, 4 4 4 1 11;, 1915. .qmsnouemem mox; i 7

It 1: herebyeertifiee that rim-51 apponra' printed apeeirieaiifl of the. abevemmbered petexitrequiring eerreeEen as-r0110": Page 5; column, line 65', for "Eonaider' reed --eona1d ei-ab1e-;:-1$lge5, second eel; 'um n, line 32, elem-1, for "(i-hue". read "group": 111 19 311,-}515 claim, ,te r "alkali-stable ineer I 53, claim 5, aftei' "l%" insei-t --to--; line 67 claim 1 for "class" read -g1'Oup--; andfiha'tfflle said Letters Pa-tent ahuilld be read with thi cerrection therein that the same may cox gram to the record of the ease in the Patent Office. 7 4 I Signed and sealed thi 25th day of December, A; D. 1911.5; 7

' Leslie Frazer First Assistant commiasiener of Patents.

- Seal) t non-aaponaeeoua eyntize tie organic line 

